The present invention relates to construction materials and more particularly to a self supporting concrete form unit of foamed polymeric material of the type described in U.S. Pat. No. 3,778,020, the description of which is incorporated herein by reference thereto.
Briefly, such a concrete form unit is of rectangular block shape and comprises a pair of rectangular sidewall members of the same size and shape which are held in spaced parallel relationship by rigid vertically positioned connecting members (sometimes also referred to in the art as tension members or spreaders) extending laterally therebetween with opposite end portions embedded in the sidewalls.
The inner faces of the sidewall members are provided with spaced laterally inwardly projecting vertically extending rib portions in which the opposite end portions of the spreaders are embedded with the portions of the inner faces of the side wall members between the rib portions and the connecting members defining vertically disposed cavities for concrete. The spreaders are conventionally made of flat, rectangular-shaped, expanded sheet metal providing a plurality of openings to enable receipt of foam material in the embedded end portions of the connecting members during manufacture of the form units and also to enable concrete to flow between the cavities during construction of a form unit wall.
In use, a number of these form units are mounted end to end in a course and one above the other in additional courses in interlocking and interconnected relationship to provide a complete permanent wall form into which reinforcing steel bars are placed and concrete or the like is then poured to form a continuous concrete reinforced wall therewithin with the form units remaining in place thereafter to form part of a building or other structure. During subsequent construction, it is usually necessary to make attachments to the wall structure formed by the concrete and the permanently attached form units. For example, as a building is being finished, it is often desirable to apply a finish covering of lath, sheetrock, paneling, or the like, which must be supportably attached to the form units. In the prior art type of form units, it has been necessary to glue finish materials to the outer surfaces of the form units or to anchor the material in the concrete inside the form units.
The present invention provides an improved concrete form unit having attachment flange means integrally mounted in the side wall members adjacent to the outer surfaces thereof for mechanically receiving and supporting mechanical fastening devices such as self tapping screws, by which finish materials or the like may be more economically and easily and securely fastened to the wall structure.
In the presently preferred embodiment of the invention, the attachment flange means are an integral part of one or more connecting members of new and improved design and which replace expanded metal spreaders in each form unit. The connecting members are made of one piece of flat sheet metal formed into a channel shaped configuration defined by a flat central connecting web portion and transversely extending flat attachment flange means portions. The flat connecting web portion which is mounted in a vertical position between the sidewall members of the form unit and has end portions embedded in the rib portions of the sidewall members, has multiple relatively large openings therein to more readily permit the flow of both plastic foam material and concrete therethrough. The openings may be arcuate or polygonal. If arcuate, they are preferably arranged in rows of staggered openings so that the percentage of the area of the openings relative to the percentage of solid interconnected metal is 75% or more. The flange portions are imperforate solid sheet metal material and extend laterally at substantially right angles to the connecting web portion in substantially parallel relationship to the outer surfaces of the side wall members and are located in relatively closely spaced relationship thereto. The connecting members of each form unit are positioned and arranged in a predetermined pattern so that the fastener attachment flange portions of each form unit will be vertically aligned between succeeding courses.